In a big pot, add the two tablespoons of olive oil. Then place the onion, the fennel bulb, the leek and the two celery stems, all well chopped (I used more celery because I like it). The chopping does not need to be specially accurate, since we are going to blend everything later. Let this cook, for ten minutes, over a low heat, without letting it become golden brown, and then add the garlic cloves, also chopped. Let it cook, for another five minutes, stirring all the time to the prevent it from sticking in the pot; however, if your mix turns out to be kind of stubborn you can always add a little bit more of olive oil.

Add the water, together with the chopped potatoes, and let it cook at medium heat for another 45 minutes, avoiding boiling. The thing with water is really up to you, some people like that thicker-pure-like texture but some others prefer it lighter and softer. After the 45 minute cooking, you crush everything with the blender, seasoning with salt and pepper and seeds to your own taste.
source: thegoodlifediary.wordpress.com